1. Field of the Invention
The present invention relates to a semiconductor integrated circuit device containing a temperature sensor. 2. Description of the Related Art
A method of protecting a semiconductor device from temperature rising, is disclosed for example in JP-A-55-55539. In accordance with this method, the voltage across the emitter and collector of a bipolar transistor having a heat radiating board made of a magnetic substance is monitored to detect the temperature of that bipolar transistor. When the detected temperature rises up to a critical temperature, the magnetic heating is stopped to prevent the breakdown of the transistor due to the excessive temperature rise.
On the other hand, in JP-A-58-77329, there is proposed a semiconductor integrated circuit device in which when a power supply voltage exceeding the operating voltage range is applied, the temperature rise of a PN junction of the transistor constituting an internal circuit is prevented by providing a circuit for suppressing the circuit current by utilizing a reverse breakdown voltage of the PN junction.
However, in the method disclosed in JP-A-55-55539, the detection of the temperature of the semiconductor device and the interruption of the magnetic heating are performed outside, and not within the semiconductor device itself. Further, when the actual reliability test is performed, the semiconductor device is encapsulated in a package and then subjected to the aging. In this connection, different kinds of packages may have different radiating capabilities. Thus, even when the reliability test is performed with a certain kind of package, the rate of temperature rise of the PN junction may be different when it is encapsulated in a different package. Therefore, in this case, an additional work is required to perform the reliability test again for that different package.
On the other hand, in the semiconductor integrated circuit device disclosed in JP-A-58-77329, the circuit for suppressing the circuit current is constructed by bipolar transistors. Therefore, such construction is unsuitable for the MOS type semiconductor integrated circuit device.